Image processor, display device including the image processor, and method of driving the display device

ABSTRACT

A display device includes a display panel including a first pixel having first and second sub-pixels for first and second color light, and a second pixel having third and fourth sub-pixels for third and second color light, an image processor to convert input image data into output image data of greater resolution, and a panel driver to display images based on the output image data, the input image data including first, second, and third input color data corresponding to the first, second, and third color light, the output image data including first, second, and third output color data corresponding to the first, second, and third color light, and the image processor for generating the first and third output color data, by performing an upscaling-rendering operation on the first and third input color data, and the second output color data, by performing an upscaling operation on the second input color data.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of, Korean PatentApplication No. 10-2017-0135452, filed on Oct. 18, 2017 in the KoreanIntellectual Property Office (KIPO), the contents of which areincorporated herein in its entirety by reference.

BACKGROUND 1. Field

Embodiments of the present inventive concept relate to display devices,and to image processors, display devices including the image processors,and methods of driving the display devices.

2. Description of the Related Art

As a resolution of a display device increases, the resolution of thedisplay device may be higher than a resolution of input image data.Thus, a high-resolution display device may employ an image processorthat performs an upscaling operation for converting low-resolution imagedata into high-resolution image data. For example, an ultra highdefinition (UHD) (e.g., 3840*2160 resolution) display device may displayan image based on full high definition (FHD) (e.g., 1920*1080resolution) image data by performing the upscaling operation.

However, although various upscaling algorithms for the upscalingoperation have been developed, a large-sized memory and a complicatedoperation may generally be used to improve upscaling performance of theupscaling algorithms.

SUMMARY

Some embodiments provide a display device capable of reducing an imageprocessing load and capable of improving image quality. Some embodimentsprovide a method of driving the display device. Some embodiments providean image processor included in the display device.

According to embodiments described herein, there is provided a displaydevice including a display panel, which includes a first pixel having afirst sub-pixel for emitting first color light and a second sub-pixelfor emitting second color light, and a second pixel having a thirdsub-pixel for emitting third color light and a fourth sub-pixel foremitting the second color light, an image processor configured toconvert input image data having a first resolution into output imagedata having a second resolution that is greater than the firstresolution, and a panel driver configured to drive the display panel todisplay an image based on the output image data, wherein the input imagedata include first input color data, second input color data, and thirdinput color data respectively corresponding to the first color light,the second color light, and the third color light, wherein the outputimage data include first output color data, second output color data,and third output color data respectively corresponding to the firstcolor light, the second color light, and the third color light, andwherein the image processor is configured to generate the first outputcolor data and the third output color data by performing anupscaling-rendering operation on the first input color data and thethird input color data, and is configured to generate the second outputcolor data by performing an upscaling operation on the second inputcolor data.

The first output color data may include first original color data andfirst additional color data, and the upscaling-rendering operation mayinclude outputting the first input color data as the first originalcolor data, and generating the first additional color data by applying afirst rendering filter to the first original color data.

The first rendering filter may generate the first additional color datafor the first sub-pixel by averaging the first original color data forsub-pixels adjacent to the first sub-pixel.

The second output color data may include second original color data thatis the same as the second input color data, and second additional colordata that are generated by applying an upscaling algorithm to the secondinput color data.

The upscaling algorithm may include at least one of an edge-directedinterpolation method, a vector extraction method, and a machine-learningmethod.

The third output color data may include third original color data andthird additional color data, and the upscaling-rendering operation mayinclude outputting the third input color data as the third originalcolor data, and generating the third additional color data by applying asecond rendering filter to the third original color data.

The first rendering filter and the second rendering filter may be thesame.

The image processor may include an input interface configured to receivethe input image data, and an upscaling-rendering engine configured togenerate the output image data based on the input image data byperforming the upscaling-rendering operation on the first input colordata and the third input color data, and by performing the upscalingoperation on the second input color data.

The image processor may include an input interface configured to receivethe input image data, an image engine configured to generate correctedimage data by performing the upscaling operation on the second inputcolor data, and an upscaling-rendering engine configured to generate theoutput image data based on the corrected image data by performing theupscaling-rendering operation on the first input color data and thethird input color data.

According to embodiments described herein, there is provided a method ofdriving a display device including a first pixel, which has a firstsub-pixel for emitting first color light and a second sub-pixel foremitting second color light, and a second pixel, which has a thirdsub-pixel for emitting third color light and a fourth sub-pixel foremitting the second color light, the method including receiving inputimage data including first input color data, second input color data,and third input color data respectively corresponding to the first colorlight, the second color light, and the third color light, generatingfirst and third output color data by performing an upscaling-renderingoperation on the first and third input color data, and second outputcolor data by performing an upscaling operation on the second inputcolor data, and outputting output image data including the first outputcolor data, the second output color data, and the third output colordata respectively corresponding to the first color light, the secondcolor light, and the third color light.

The first output color data may include first original color data andfirst additional color data, and the upscaling-rendering operation mayinclude outputting the first input color data as the first originalcolor data, and generating the first additional color data by applying afirst rendering filter to the first original color data.

Applying the first rendering filter may include generating the firstadditional color data for the first sub-pixel by averaging the firstoriginal color data for sub-pixels adjacent to the first sub-pixel.

The second output color data may include second original color data thatis the same as the second input color data, and second additional colordata that are generated by applying an upscaling algorithm to the secondinput color data.

The upscaling algorithm may include at least one of an edge-directedinterpolation method, a vector extraction method, and a machine-learningmethod.

The third output color data may include third original color data andthird additional color data, and the upscaling-rendering operation mayinclude outputting the third input color data as the third originalcolor data, and generating the third additional color data by applying asecond rendering filter to the third original color data.

The first rendering filter and the second rendering filter may be thesame.

According to embodiments described herein, there is provided an imageprocessor included in a display device including a first pixel, whichhas a first sub-pixel for emitting first color light and a secondsub-pixel for emitting second color light, and a second pixel, which hasa third sub-pixel for emitting third color light and a fourth sub-pixelfor emitting the second color light, the image processor including aninput interface configured to receive input image data including firstinput color data, second input color data, and third input color datarespectively corresponding to the first color light, the second colorlight, and the third color light, and an upscaling-rendering engineconfigured to generate output image data based on the input image databy performing an upscaling-rendering operation on the first input colordata and the third input color data, and by performing an upscalingoperation on the second input color data.

The output image data may include first output color data, second outputcolor data, and third output color data respectively corresponding tothe first color light, the second color light, and the third colorlight, the first output color data may include first original color dataand first additional color data, and the upscaling-rendering operationmay include outputting the first input color data as the first originalcolor data, and generating the first additional color data by applying afirst rendering filter to the first original color data.

The first rendering filter may generate the first additional color datafor the first sub-pixel by averaging the first original color data forsub-pixels adjacent to the first sub-pixel.

The second output color data may include second original color data thatis the same as the second input color data, and second additional colordata that are generated by applying an upscaling algorithm to the secondinput color data.

As described above, the display device according to embodiments may havea pentile pixel arrangement structure, may perform anupscaling-rendering operation on first and third color data, and mayperform an upscaling operation on second color data. Accordingly, in thedisplay device according to embodiments, when compared with a displaydevice that performs a sub-pixel rendering operation after performing anupscaling operation on the entirety of the input image data, aprocessing amount may be reduced, and image quality may be improved.

The method of driving the display device according to embodiments mayperform the upscaling operation or the upscaling-rendering operationaccording to types (or colors) of sub-pixels based on a pixelarrangement structure, thereby displaying a more clear image. Also, theimage processor according to embodiments may efficiently process imagedata provided to the display device having the pentile pixel arrangementstructure.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative, non-limiting embodiments will be more clearly understoodfrom the following detailed description in conjunction with theaccompanying drawings.

FIG. 1 is a block diagram illustrating a host device and a displaydevice according to an embodiment.

FIG. 2 is an example of an image processor included in a display deviceillustrated in FIG. 1.

FIGS. 3A and 3B are diagrams for describing an example where an imageprocessor included in a display device of FIG. 1 generates output imagedata by performing an upscaling-rendering operation and an upscalingoperation.

FIGS. 4 and 5 are diagrams for describing an example where first andthird output color data are generated by an upscaling-renderingoperation.

FIG. 6 is a flowchart illustrating a method of driving a display deviceaccording to an embodiment.

FIG. 7 is a block diagram illustrating another example of an imageprocessor included in a display device of FIG. 1.

FIG. 8 is a block diagram illustrating an example of an image processoraccording to a comparative embodiment.

FIGS. 9A through 9C are diagrams for describing an example where animage processor of FIG. 8 sequentially performs an upscaling operationand a sub-pixel rendering operation to generate output image data.

FIG. 10 is a diagram for describing an effect of image qualityimprovement by a display device illustrated in FIG. 1.

DETAILED DESCRIPTION

Features of the inventive concept and methods of accomplishing the samemay be understood more readily by reference to the following detaileddescription of embodiments and the accompanying drawings. Hereinafter,embodiments will be described in more detail with reference to theaccompanying drawings. The present invention, however, may be embodiedin various different forms, and should not be construed as being limitedto only the illustrated embodiments herein. Rather, these embodimentsare provided as examples so that this disclosure will be thorough andcomplete, and will fully convey the aspects and features of the presentinvention to those skilled in the art. Accordingly, processes, elements,and techniques that are not necessary to those having ordinary skill inthe art for a complete understanding of the aspects and features of thepresent invention may not be described. Unless otherwise noted, likereference numerals denote like elements throughout the attached drawingsand the written description, and thus, descriptions thereof will not berepeated. Further, parts not related to the description of theembodiments might not be shown to make the description clear. In thedrawings, the relative sizes of elements, layers, and regions may beexaggerated for clarity.

In the following description, for the purposes of explanation, numerousspecific details are set forth to provide a thorough understanding ofvarious embodiments. It is apparent, however, that various embodimentsmay be practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form in order to avoid unnecessarilyobscuring various embodiments.

It will be understood that, although the terms “first,” “second,”“third,” etc., may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, a first element, component, region, layer or sectiondescribed below could be termed a second element, component, region,layer or section, without departing from the spirit and scope of thepresent invention.

It will be understood that when an element, layer, region, or componentis referred to as being “on,” “connected to,” or “coupled to” anotherelement, layer, region, or component, it can be directly on, connectedto, or coupled to the other element, layer, region, or component, or oneor more intervening elements, layers, regions, or components may bepresent. However, “directly connected/directly coupled” refers to onecomponent directly connecting or coupling another component without anintermediate component. Meanwhile, other expressions describingrelationships between components such as “between,” “immediatelybetween” or “adjacent to” and “directly adjacent to” may be construedsimilarly. In addition, it will also be understood that when an elementor layer is referred to as being “between” two elements or layers, itcan be the only element or layer between the two elements or layers, orone or more intervening elements or layers may also be present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a” and “an” are intendedto include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “have,” “having,” “includes,” and“including,” when used in this specification, specify the presence ofthe stated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

Various embodiments are described herein with reference to sectionalillustrations that are schematic illustrations of embodiments and/orintermediate structures. As such, variations from the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Further, specific structural orfunctional descriptions disclosed herein are merely illustrative for thepurpose of describing embodiments according to the concept of thepresent disclosure. Thus, embodiments disclosed herein should not beconstrued as limited to the particular illustrated shapes of regions,but are to include deviations in shapes that result from, for instance,manufacturing. For example, an implanted region illustrated as arectangle will, typically, have rounded or curved features and/or agradient of implant concentration at its edges rather than a binarychange from implanted to non-implanted region. Likewise, a buried regionformed by implantation may result in some implantation in the regionbetween the buried region and the surface through which the implantationtakes place. Thus, the regions illustrated in the drawings are schematicin nature and their shapes are not intended to illustrate the actualshape of a region of a device and are not intended to be limiting.Additionally, as those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the present disclosure.

The electronic or electric devices and/or any other relevant devices orcomponents according to embodiments of the present invention describedherein may be implemented utilizing any suitable hardware, firmware(e.g. an application-specific integrated circuit), software, or acombination of software, firmware, and hardware. For example, thevarious components of these devices may be formed on one integratedcircuit (IC) chip or on separate IC chips. Further, the variouscomponents of these devices may be implemented on a flexible printedcircuit film, a tape carrier package (TCP), a printed circuit board(PCB), or formed on one substrate. Further, the various components ofthese devices may be a process or thread, running on one or moreprocessors, in one or more computing devices, executing computer programinstructions and interacting with other system components for performingthe various functionalities described herein. The computer programinstructions are stored in a memory which may be implemented in acomputing device using a standard memory device, such as, for example, arandom access memory (RAM). The computer program instructions may alsobe stored in other non-transitory computer readable media such as, forexample, a CD-ROM, flash drive, or the like. Also, a person of skill inthe art should recognize that the functionality of various computingdevices may be combined or integrated into a single computing device, orthe functionality of a particular computing device may be distributedacross one or more other computing devices without departing from thespirit and scope of the described embodiments.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the present invention belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present specification, and should not be interpreted in an idealizedor overly formal sense, unless expressly so defined herein.

FIG. 1 is a block diagram illustrating a host device and a displaydevice according to an embodiment.

Referring to FIG. 1, a display device 1000 includes an image processor100, a panel driver 200, and a display panel 300. The display device1000 may receive input image data IDATA from a host device 10, and maydisplay an image based on the input image data IDATA. In someembodiments, the display device 1000 may be an organic light emittingdiode (OLED) display device. The host device 10 may be a graphiccontroller, an application processor, or any device that provides theinput image data IDATA to the display device 1000.

The image processor 100 may convert the input image data IDATA intooutput image data ODATA corresponding to a resolution of, and a pixelarrangement structure of, the display panel 300. In some embodiments,the image processor 100 may convert the input image data IDATA having afirst resolution into the output image data ODATA having a secondresolution that is greater than the first resolution. Thus, the imageprocessor 100 may perform an upscaling operation that converts the lowresolution image data IDATA into the high resolution image data ODATA.The input image data IDATA may include first input color data, secondinput color data, and third input color data respectively correspondingto first color light, second color light, and third color light.

The output image data ODATA may include first output color data, secondoutput color data, and third output color data respectivelycorresponding to the first color light, the second color light, and thethird color light. For example, each of the input image data IDATA andthe output image data ODATA may include red data, green data, and bluedata. The image processor 100 may selectively perform anupscaling-rendering operation or an upscaling operation according totypes (or colors) of sub-pixels by considering the pixel arrangementstructure of the display panel 300, thereby improving image processingefficiency.

Here, the upscaling-rendering operation may be an operation in which theupscaling operation, which converts low definition image data into highdefinition image data, and a down-sampling operation/sub-pixel renderingoperation, which converts RGB image data into image data correspondingto a pentile pixel arrangement structure (e.g., RGBG image data), aremerged. The upscaling-rendering operation may output the input imagedata IDATA as original color data, and may generate additional colordata by applying a rendering filter to the original color data (or theinput image data IDATA) without performing a separate upscalingoperation. The upscaling-rendering operation may generate firstadditional color data by applying a first rendering filter to firstoriginal color data (or the first input color data), and may generatethird additional color data by applying a second rendering filter tothird original color data (or the third input color data). For example,the red data and the blue data of the input image data IDATA may beprocessed by the upscaling-rendering operation using the first andsecond rendering filters to correspond to red sub-pixels and bluesub-pixels, respectively.

The upscaling operation may increase a resolution of the image data. Theupscaling operation may generate second additional color data byapplying an upscaling algorithm to the second input color data. Forexample, the output image data ODATA for green sub-pixels included inthe display panel 300 may be generated by performing the upscalingoperation on the green data of the input image data IDATA. In someembodiments, the upscaling algorithm may include at least one of anedge-directed interpolation method, a vector extraction method, and amachine-learning method.

The panel driver 200 may provide a driving signal DS to the displaypanel 300 to display an image based on the output image data ODATA. Insome embodiments, the panel driver 200 may include a scan driver thatprovides a scan signal, and a data driver that converts the output imagedata ODATA into analog data signals and then outputs the analog datasignals.

The display panel 300 may include a plurality of pixels. In someembodiments, the display panel 300 may have a pentile pixel arrangementstructure. In the display panel 300, first pixels each including a firstsub-pixel for emitting first color light (e.g., red light) and a secondsub-pixel for emitting second color light (e.g., green light), andsecond pixels each including a third sub-pixel for emitting third colorlight (e.g., blue light) and a fourth sub-pixel for emitting the secondcolor light (e.g., the green light) may be alternately arranged in amatrix form.

FIG. 2 is an example of an image processor included in a display deviceillustrated in FIG. 1.

Referring to FIG. 2, an image processor 100 a may include an inputinterface 110, an image engine 120 a, and an upscaling-rendering engine130 a.

The input interface 110 may receive input image data IDATA having afirst resolution, and may provide the input image data IDATA to theimage engine 120 a. In some embodiments, the first resolution may beless than a second resolution of a display panel. For example, the firstresolution may correspond to full high definition (FHD) (or a 1920*1080resolution), and the second resolution may correspond to ultra highdefinition (UHD) (or a 3840*2160 resolution). The input image data IDATAmay include first input color data (e.g., input red data), second inputcolor data (e.g., input green data), and third input color data (e.g.,input blue data), which respectively correspond to first color light(e.g., red light), second color light (e.g., green light), and thirdcolor light (e.g., blue light). The input interface 110 may be a displayinterface of a mobile device, such as a mobile industry processorinterface (MIPI), a display serial interface (DSI), etc.

The image engine 120 a may process digital image data (e.g., the inputimage data IDATA) to improve image quality, such as sharpness, noisereduction, light and darkness contrast, color contrast, etc. Forexample, the image engine 120 a may be a digital natural image engine(DNIe) that adjusts sharpness, noise reduction, light and darknesscontrast, color contrast, etc. Thus, the image engine 120 a may generateimage processed data PD by processing the input image data IDATA.

The upscaling-rendering engine 130 a may generate output image dataODATA1 by performing an upscaling-rendering operation on the first andthird input color data, and by performing an upscaling operation on thesecond input color data, based on the input image data IDATA (or basedon the image processed data PD). The output image data ODATA1 mayinclude first output color data (e.g., output red data), second outputcolor data (e.g., output green data), and third output color data (e.g.,output blue data) respectively corresponding to the first color light,the second color light, and the third color light.

In some embodiments, the first output color data may include firstoriginal color data that is the same as the first input color data, andfirst additional color data that is generated based on the firstoriginal color data (or the first input color data), and the thirdoutput color data may include third original color data that is the sameas the third input color data and third additional color data that isgenerated based on the third original color data (or the third inputcolor data). The upscaling-rendering operation may generate the firstand third additional color data by respectively applying first andsecond rendering filters to the first and third original color data (orto the first and third input color data). The first rendering filter maygenerate the first additional color data for a first sub-pixel based onthe first input color data for sub-pixels that are adjacent to the firstsub-pixel. The second rendering filter may generate the third additionalcolor data for a third sub-pixel based on the third input color data forsub-pixels that are adjacent to the third sub-pixel.

In some embodiments, the second output color data may include secondoriginal color data that is the same as the second input color data, andsecond additional color data that is generated by applying an upscalingalgorithm to the second input color data.

The upscaling-rendering operation and the upscaling operation will bedescribed below with reference to FIGS. 3A, 3B, 4, and 5.

Although FIG. 2 illustrates an example where the image processor 100 aincludes the input interface 110, the image engine 120 a and theupscaling-rendering engine 130 a, a configuration of the image processor100 a may not necessarily be limited thereto. For example, the imageprocessor 100 a may omit the image engine 120 a, or may further includean output interface for communicating with a panel driver.

FIGS. 3A and 3B are diagrams for describing an example where an imageprocessor included in a display device of the embodiment of FIG. 1generates output image data by performing an upscaling-renderingoperation and an upscaling operation, and FIGS. 4 and 5 are diagrams fordescribing an example where first and third output color data aregenerated by an upscaling-rendering operation.

As illustrated in FIG. 3A, an image processor may receive, as inputimage data, RGB-type image data having a first resolution. For example,the input image data may include input red data, input green data, andinput blue data respectively for a red sub-pixel (e.g., R11), a greensub-pixel (e.g., G11), and a blue sub-pixel (e.g., B11) included in eachpixel (e.g., IPX(1,1)). The first resolution may be FHD (e.g., a1920*1080 resolution). Thus, the input image data may include 1920*1080input red data, 1920*1080 input green data, and 1920*1080 input bluedata.

As illustrated in FIG. 3B, a display panel may have a pentile pixelarrangement structure. For example, the display panel may have astructure where first pixels (e.g., first pixels OPX(1,1), OPX(1,3),OPX(1,5), OPX(2,2), OPX(2,4), OPX(2,6), OPX(3,1), OPX(3,3), OPX(3,5),OPX(4,2), OPX(4,4), and OPX(4,6)), which each include a red sub-pixel(e.g., a respective one of red sub-pixels R11, R13, R15, R22, R24, R26,R31, R33, R35, R42, R44, and R46) and a green sub-pixel (e.g., arespective one of green sub-pixels G11, G13, G15, G22, G24, G26, G31,G33, G35, G42, G44, and G46), and second pixels (e.g., second pixelsOPX(1,2), OPX(1,4), OPX(1,6), OPX(2,1), OPX(2,3), OPX(2,5), OPX(3,2),OPX(3,4), OPX(3,6), OPX(4,1), OPX(4,3), and OPX(4,5)), which eachinclude a blue sub-pixel (e.g., a respective one of blue sub-pixels B12,B14, B16, B21, B23, B25, B32, B34, B36, B41, B43, and B45) and a greensub-pixel (e.g., a respective one of green sub-pixels G12, G14, G16,G21, G23, G25, G32, G34, G36, G41, G43, and G45), are alternatelyarranged in a horizontal direction and a vertical direction. A secondresolution of the display panel may be UHD (e.g., a 3840*2160resolution). Thus, the display panel may include 1920*2160 redsub-pixels, 3840*2160 green sub-pixels and 1920*2160 blue sub-pixels.

The image processor may convert the input image data having the firstresolution into output image data having the second resolution, which issuitable for the pixel arrangement structure of the display panel. Thus,the output image data may include 1920*2160 output red data, 3840*2160output green data and 1920*2160 output blue data.

The image processor may convert the 1920*1080 input red data into the1920*2160 output red data, and may convert the 1920*1080 input blue datainto the 1920*2160 output blue data. Because the input red data and theinput blue data are required to be doubled in a vertical direction, theupscaling-rendering operation may output the input red data and theinput blue data as they are input, and may generate additional red dataand additional blue data that are the same in number as the input reddata and the input blue data.

Referring to FIGS. 3A, 3B, and 4, with respect to red sub-pixels, theoutput red data for red sub-pixels R11, R13, and R15 respectivelyincluded in output pixels OPX(1,1), OPX(1,3), and OPX(1,5) may be set asthe input red data for sub-pixels R11, R12, and R13 respectivelyincluded in input pixels IPX(1,1), IPX(1,2), and IPX(1,3). Here, theoutput pixels may be the pixels (of the display panel) arranged in thepentile pixel arrangement structure, and the input pixels may be thepixels (corresponding to the input image data) arranged in an RGB pixelarrangement structure. Further, the output red data for red sub-pixelsR31, R33, and R35 respectively included in output pixels OPX(3,1),OPX(3,3), and OPX(3,5) may be set as the input red data for sub-pixelsR21, R22, and R23 respectively included in input pixels IPX(2,1),IPX(2,2), and IPX(2,3). Thus, the output red data for the red sub-pixelslocated in odd-numbered rows may be original red data (or original dataORIGINAL) that is the same as the input red data.

However, the output red data for the red sub-pixels located ineven-numbered rows may be additional red data that is different from theinput red data. The image processor may generate the additional red data(or upscaling-rendering data UP-RENDER) by applying a first renderingfilter to the original red data (or the input red data).

For example, in FIG. 4, the output red data for a red sub-pixel R22included in an output pixel OPX(2,2) may be set as an average value ofthe original red data set for adjacent red sub-pixels R11, R13, R31, andR33 included in adjacent output pixels OPX(1,1), OPX(1,3), OPX(3,1), andOPX(3,3) (e.g., an average value of the input red data for redsub-pixels R11, R12, R21, and R22 included in input pixels IPX(1,1),IPX(1,2), IPX(2,1), and IPX(2,2)). Further, the output red data for ared sub-pixel R24 included in an output pixel OPX(2,4) may be set as anaverage value of the original red data set for adjacent red sub-pixelsR13, R15, R33, and R35 included in adjacent output pixels OPX(1,3),OPX(1,5), OPX(3,3), and OPX(3,5).

Referring to FIGS. 3A, 3B, and 5, with respect to blue sub-pixels, theoutput blue data for blue sub-pixels B12, B14, and B16 respectivelyincluded in output pixels OPX(1,2), OPX(1,4), and OPX(1,6) may be set asthe input blue data for sub-pixels B11, B12, and B13 respectivelyincluded in input pixels IPX(1,1), IPX(1,2), and IPX(1,3). Further, theoutput blue data for blue sub-pixels B32, B34, and B36 respectivelyincluded in output pixels OPX(3,2), OPX(3,4), and OPX(3,6) may be set asthe input blue data for sub-pixels B21, B22, and B23 respectivelyincluded in input pixels IPX(2,1), IPX(2,2), and IPX(2,3). Thus, theoutput blue data for the blue sub-pixels located in odd-numbered rowsmay be original blue data (or original data ORIGINAL) that is the sameas the input blue data.

However, the output blue data for the blue sub-pixels located ineven-numbered rows may be additional blue data that is different fromthe input blue data. The image processor may generate the additionalblue data (or upscaling-rendering data UP-RENDER) by applying a secondrendering filter to the original blue data (or the input blue data). Forexample, in FIG. 5, the output blue data for a blue sub-pixel B23included in an output pixel OPX(2,3) may be set as an average value ofthe original blue data set for adjacent blue sub-pixels B12, B14, B32,and B34 included in adjacent output pixels OPX(1,2), OPX(1,4), OPX(3,2),and OPX(3,4) (e.g., an average value of the input blue data for bluesub-pixels B11, B12, B21, and B22 included in input pixels IPX(1,1),IPX(1,2), IPX(2,1), and IPX(2,2)). Further, the output blue data for ablue sub-pixel B25 included in an output pixel OPX(2,5) may be set as anaverage value of the original blue data set for adjacent blue sub-pixelsB14, B16, B34, and B36 included in adjacent output pixels OPX(1,4),OPX(1,6), OPX(3,4), and OPX(3,6). The output blue data for a bluesub-pixel B21 included in an output pixel OPX(2,1) located at an edgeportion of the display panel may be set as an average value of theoriginal blue data set for two adjacent blue sub-pixels B12 and B32included in two adjacent output pixels OPX(1,2) and OPX(3,2).

The image processor may convert the 1920*1080 input green data into the3840*2160 output green data. Because the input green data are requiredto be doubled not only in a vertical direction, but also in a horizontaldirection, the upscaling operation may output the input green data asthey are input, and may generate additional green data in an amount thatis three times as many as the input green data.

Referring to FIGS. 3A and 3B, with respect to green sub-pixels, theoutput green data for green sub-pixels G11, G13, and G15 respectivelyincluded in output pixels OPX(1,1), OPX(1,3), and OPX(1,5) may be set asthe input green data for sub-pixels G11, G12, and G13 respectivelyincluded in input pixels IPX(1,1), IPX(1,2), and IPX(1,3). Further, theoutput green data for green sub-pixels G31, G33, and G35 respectivelyincluded in output pixels OPX(3,1), OPX(3,3), and OPX(3,5) may be set asthe input blue data for sub-pixels G21, G22, and G23 respectivelyincluded in input pixels IPX(2,1), IPX(2,2), and IPX(2,3). Thus, theoutput green data for the green sub-pixels located both in anodd-numbered row and in an odd-numbered column may be original greendata (or original data ORIGINAL) the same as the input green data.

However, the output green data for green sub-pixels G12, G14, G16, G21,G22, G23, G24, G25, G26, G32, G34, G36, G41, G42, G43, G44, G45, G46located in either of an even-numbered row or an even-numbered column maybe the additional green data, which is different from the input greendata. The image processor may generate the additional green data (orupscaling data UPS) by applying an upscaling algorithm to the inputgreen data. The upscaling algorithm may include at least one of anedge-directed interpolation method, a vector extraction method, and amachine-learning method. The edge-directed interpolation method may beperformed such that an edge of an image is maintained after theupscaling operation. The vector extraction method may convert an imageinto a vector expression regardless of a resolution, and may thenconvert the vector expression into an image having a desired resolution.The machine-learning method may perform a scaling operation usingmachine learning, such as a deep neural network method.

Although FIGS. 4 and 5 illustrate examples where the first and secondrendering filters are applied corresponding to data of four adjacentsub-pixels, the first and second rendering filters are not limitedthereto. For example, in other embodiments, the first and secondrendering filters may be applied to data for sub-pixels located in aprevious row to reduce a size of a line memory. Further, in someembodiments, the first rendering filter and the second rendering filtermay be different filters.

FIG. 6 is a flowchart illustrating a method of driving a display deviceaccording to an embodiment.

Referring to FIG. 6, a method of the embodiment of FIG. 6 may drive adisplay device (of a pentile pixel arrangement structure) including afirst pixel, which has a red sub-pixel for emitting red light and agreen sub-pixel for emitting green light, and a second pixel, which hasa blue sub-pixel for emitting blue light and a green sub-pixel foremitting the green light, to display a clear image.

In the described method, input image data having a first resolution andincluding input red data, input green data, and input blue data, whichrespectively correspond to the red light, the green light, and the bluelight, may be received (S110).

The first resolution may be compared with a second resolution, whichcorresponds to the resolution of the display device (S120).

If the first resolution is less than the second resolution (S120: YES),output green data may be generated by performing an upscaling operationon the input green data among the input image data (S130: YES and S140),and output red data and output blue data may be generated by performingan upscaling-rendering operation on the input red data and the inputblue data among the input image data (S130: NO and S150). Because theupscaling-rendering operation and the upscaling operation are describedabove, duplicated descriptions thereof are omitted.

Alternatively, if the first resolution is greater than or equal to thesecond resolution (S120: NO), output image data may be generated byperforming a sub-pixel rendering operation corresponding to the pentilepixel arrangement structure and/or a downscaling operation to decreasethe resolution of the input image (S160).

The output image data including the output red data, the output greendata, and the output blue data may be output to display an imagecorresponding to the output image data (S170).

FIG. 7 is a block diagram illustrating another example of an imageprocessor included in a display device illustrated in FIG. 1.

Referring to FIG. 7, an image processor 100 b may include an inputinterface 110, an image engine 120 b, and an upscaling-rendering engine130 b. The image processor 100 b of FIG. 7 may have similarconfigurations and operations to an image processor 100 a of theembodiment of FIG. 2, except that an upscaling operation is performed bythe image engine 120 b. The same reference numerals may denote the sameor similar components, and duplicated descriptions may be omitted.

The input interface 110 may receive input image data IDATA having afirst resolution, and may provide the input image data IDATA to theimage engine 120 b.

The image engine 120 b may process digital image data (e.g., the inputimage data IDATA) to improve image quality, such as sharpness, noisereduction, light and darkness contrast, color contrast, etc. Further,the image engine 120 b may generate corrected image data CD byperforming the upscaling operation on second input color data (e.g.,input green data).

The upscaling-rendering engine 130 b may generate output image dataODATA2 by performing an upscaling-rendering operation on first inputcolor data (e.g., input green data) and third input color data (e.g.,input blue data) based on the corrected image data CD.

FIG. 8 is a block diagram illustrating an example of an image processoraccording to a comparative embodiment, FIGS. 9A through 9C are diagramsfor describing an example where an image processor of FIG. 8sequentially performs an upscaling operation and a sub-pixel renderingoperation to generate output image data, and FIG. 10 is a diagram fordescribing an effect of image quality improvement by a display device ofthe embodiment illustrated in FIG. 1.

Referring to FIGS. 8, 9A, 9B, 9C, and 10, a comparative image processor500 may include an input interface 510, an image engine 520, and asub-pixel rendering engine 530.

The input interface 510 may receive RGB-type input image data IDATAhaving a first resolution. As illustrated in FIG. 9A, the input imagedata IDATA may include input red data, input green data, and input bluedata respectively for a red sub-pixel (e.g., R11), a green sub-pixel(e.g., G11), and a blue sub-pixel (e.g., B11) included in each pixel(e.g., IPX(1,1)). The first resolution may be FHD (e.g., a 1920*1080resolution). In this case, the input image data IDATA may include1920*1080 input red data, 1920*1080 input green data, and 1920*1080input blue data.

The image engine 520 may convert the input image data IDATA having thefirst resolution into scaled image data SD having a second resolution byperforming an upscaling operation on the input image data IDATA. Asillustrated in FIG. 9B, the image engine 520 may generate the scaledimage data SD by generating upscaling data UPS by applying an upscalingalgorithm to the input image data IDATA (e.g., original data ORIGINAL).The upscaling algorithm may include an edge-directed interpolationmethod, a vector extraction method, or a machine-learning method. Thesecond resolution may be UHD (e.g., a 3840*2160 resolution). In thiscase, the scaled image data SD may include 3840*2160 red data, 3840*2160green data, and 3840*2160 blue data.

The sub-pixel rendering engine 530 may perform a sub-pixel renderingoperation that down-samples the scaled image data SD to correspond to apixel arrangement structure of a display device. Accordingly, the scaledimage data SD may be converted into output image data ODATA3corresponding to the pixel arrangement structure. As illustrated in FIG.9C, each pixel included in a display device having a pentile pixelarrangement structure may correspond to a first pixel (e.g., OPX(1,1))including a red sub-pixel (e.g., R11) and a green sub-pixel (e.g., G11),or a second pixel (e.g., OPX(1,2)) including a blue sub-pixel (e.g.,B12) and a green sub-pixel (e.g., G12). Thus, the output image dataODATA3 may include 1920*2160 output red data, 3840*2160 output greendata, and 1920*2160 output blue data.

Each of the output red data and the output blue data may be set byreferring to the scaled image data SD for sub-pixels that are adjacentin a horizontal direction, and thus may correspond to sub-pixelrendering-after-upscaling data UPS & SPR. For example, the output reddata for a red sub-pixel R11 included in an output pixel OPX(1,1) may beset as an average value of the scaled image data SD for red sub-pixelsR11 and R12 respectively included in scaled pixels SPX(1,1) andSPX(1,2). The output red data for a red sub-pixel R13 included in anoutput pixel OPX(1,3) may be set as an average value of the scaled imagedata SD for red sub-pixels R13 and R14 respectively included in scaledpixels SPX(1,3) and SPX(1,4). The output blue data for a blue sub-pixelB12 included in an output pixel OPX(1,2) may be set as an average valueof the scaled image data SD for blue sub-pixels B11 and B12 respectivelyincluded in scaled pixels SPX(1,1) and SPX(1,2). The output blue datafor a blue sub-pixel B14 included in an output pixel OPX(1,4) may be setas an average value of the scaled image data SD for blue sub-pixels B13and B14 respectively included in scaled pixels SPX(1,3) and SPX(1,4).

The output green data have one-to-one correspondence with the green dataof the scaled image data SD, and thus the green data of the scaled imagedata SD, as it is, may be output as the output green data.

The comparative image processor 500 may perform the upscaling operationon the red, green, and blue data of the input image data IDATA, and thenmay perform the sub-pixel rendering operation. Thus, the red and bluedata of the output image data ODATA3 do not include the original dataORIGINAL that is the same as the input image data IDATA. However, theimage processor 100 a of FIG. 2 (or an image processor 100 b of FIG. 7)according to an embodiment may perform an upscaling-rendering operationon the red and blue data, and may perform the upscaling operation on thegreen data. Thus, at least a portion (e.g., a half) of the red and bluedata may be the original data ORIGINAL that is the same as the inputimage data IDATA. Accordingly, compared with the comparative imageprocessor 500 of FIG. 8, the image processor 100 a of the embodiment ofFIG. 2 (or the image processor 100 b of the embodiment of FIG. 7) mayhave the reduced number of total operations and the improved imagequality.

As illustrated in FIG. 10, as compared to a first image SM1 processed bythe comparative image processor 500 of FIG. 8, a second image SM2processed by the image processor 100 a of the embodiment of FIG. 2 mayhave clear lines and characters, which can be perceived by the nakedeye. Because both of image degradation by the upscaling operation andimage degradation by the sub-pixel rendering operation occur in thecomparative image processor 500 of FIG. 8, the image quality of thefirst image SM1 may be relatively low. However, the image processor 100a of the embodiment of FIG. 2 may perform one operation (e.g., theupscaling-rendering operation) where the upscaling operation and thesub-pixel rendering operation are merged, and thus may improveefficiency of image processing and may improve the image quality of thesecond image SM2.

The foregoing is illustrative of embodiments for an image processor, adisplay device including the image processor and a method of driving thedisplay device and is not to be construed as limiting thereof. Althougha few embodiments have been described, those skilled in the art willreadily appreciate that many modifications are possible in theembodiments without materially departing from the novel teachings andadvantages of the present inventive concept. Accordingly, all suchmodifications are intended to be included within the scope of thepresent inventive concept as defined in the claims. For example,although an OLED display device is described above, a type of thedisplay device may not be limited to the OLED display device. Therefore,it is to be understood that the foregoing is illustrative of variousembodiments and is not to be construed as limited to the specificembodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the appended claims, with functional equivalentsthereof to be included.

What is claimed is:
 1. A display device comprising: a display panelcomprising: a first pixel having a first sub-pixel for emitting firstcolor light and a second sub-pixel for emitting second color light; anda second pixel having a third sub-pixel for emitting third color lightand a fourth sub-pixel for emitting the second color light; an imageprocessor configured to convert input image data having a firstresolution into output image data having a second resolution that isgreater than the first resolution; and a panel driver configured todrive the display panel to display an image based on the output imagedata, wherein the input image data comprise first input color data,second input color data, and third input color data respectivelycorresponding to the first color light, the second color light, and thethird color light, wherein the output image data comprise first outputcolor data, second output color data, and third output color datarespectively corresponding to the first color light, the second colorlight, and the third color light, and wherein the image processor isconfigured to generate the first output color data and the third outputcolor data by performing an upscaling-rendering operation on the firstinput color data and the third input color data, and is configured togenerate the second output color data by performing an upscalingoperation on the second input color data.
 2. The display device of claim1, wherein the first output color data comprise first original colordata and first additional color data, and wherein theupscaling-rendering operation comprises outputting the first input colordata as the first original color data, and generating the firstadditional color data by applying a first rendering filter to the firstoriginal color data.
 3. The display device of claim 2, wherein the firstrendering filter generates the first additional color data for the firstsub-pixel by averaging the first original color data for sub-pixelsadjacent to the first sub-pixel.
 4. The display device of claim 2,wherein the second output color data comprise second original color datathat is the same as the second input color data, and second additionalcolor data that are generated by applying an upscaling algorithm to thesecond input color data.
 5. The display device of claim 4, wherein theupscaling algorithm comprises at least one of an edge-directedinterpolation method, a vector extraction method, and a machine-learningmethod.
 6. The display device of claim 2, wherein the third output colordata comprise third original color data and third additional color data,and wherein the upscaling-rendering operation comprises outputting thethird input color data as the third original color data, and generatingthe third additional color data by applying a second rendering filter tothe third original color data.
 7. The display device of claim 6, whereinthe first rendering filter and the second rendering filter are the same.8. The display device of claim 1, wherein the image processor comprises:an input interface configured to receive the input image data; and anupscaling-rendering engine configured to generate the output image databased on the input image data by performing the upscaling-renderingoperation on the first input color data and the third input color data,and by performing the upscaling operation on the second input colordata.
 9. The display device of claim 1, wherein the image processorcomprises: an input interface configured to receive the input imagedata; an image engine configured to generate corrected image data byperforming the upscaling operation on the second input color data; andan upscaling-rendering engine configured to generate the output imagedata based on the corrected image data by performing theupscaling-rendering operation on the first input color data and thethird input color data.
 10. A method of driving a display devicecomprising a first pixel, which has a first sub-pixel for emitting firstcolor light and a second sub-pixel for emitting second color light, anda second pixel, which has a third sub-pixel for emitting third colorlight and a fourth sub-pixel for emitting the second color light, themethod comprising: receiving input image data comprising first inputcolor data, second input color data, and third input color datarespectively corresponding to the first color light, the second colorlight, and the third color light; generating first and third outputcolor data by performing an upscaling-rendering operation on the firstand third input color data, and second output color data by performingan upscaling operation on the second input color data; and outputtingoutput image data comprising the first output color data, the secondoutput color data, and the third output color data respectivelycorresponding to the first color light, the second color light, and thethird color light.
 11. The method of claim 10, wherein the first outputcolor data comprise first original color data and first additional colordata, and wherein the upscaling-rendering operation comprises outputtingthe first input color data as the first original color data, andgenerating the first additional color data by applying a first renderingfilter to the first original color data.
 12. The method of claim 11,wherein applying the first rendering filter comprises generating thefirst additional color data for the first sub-pixel by averaging thefirst original color data for sub-pixels adjacent to the firstsub-pixel.
 13. The method of claim 11, wherein the second output colordata comprise second original color data that is the same as the secondinput color data, and second additional color data that are generated byapplying an upscaling algorithm to the second input color data.
 14. Themethod of claim 13, wherein the upscaling algorithm comprises at leastone of an edge-directed interpolation method, a vector extractionmethod, and a machine-learning method.
 15. The method of claim 11,wherein the third output color data comprise third original color dataand third additional color data, and wherein the upscaling-renderingoperation comprises outputting the third input color data as the thirdoriginal color data, and generating the third additional color data byapplying a second rendering filter to the third original color data. 16.The method of claim 15, wherein the first rendering filter and thesecond rendering filter are the same.
 17. An image processor for adisplay device comprising a first pixel, which has a first sub-pixel foremitting first color light and a second sub-pixel for emitting secondcolor light, and a second pixel, which has a third sub-pixel foremitting third color light and a fourth sub-pixel for emitting thesecond color light, the image processor comprising: an input interfaceconfigured to receive input image data comprising first input colordata, second input color data, and third input color data respectivelycorresponding to the first color light, the second color light, and thethird color light; and an upscaling-rendering engine configured togenerate output image data based on the input image data by performingan upscaling-rendering operation on the first input color data and thethird input color data, and by performing an upscaling operation on thesecond input color data.
 18. The image processor of claim 17, whereinthe output image data comprise first output color data, second outputcolor data, and third output color data respectively corresponding tothe first color light, the second color light, and the third colorlight, wherein the first output color data comprise first original colordata and first additional color data, and wherein theupscaling-rendering operation comprises outputting the first input colordata as the first original color data, and generating the firstadditional color data by applying a first rendering filter to the firstoriginal color data.
 19. The image processor of claim 18, wherein thefirst rendering filter generates the first additional color data for thefirst sub-pixel by averaging the first original color data forsub-pixels adjacent to the first sub-pixel.
 20. The image processor ofclaim 18, wherein the second output color data comprise second originalcolor data that is the same as the second input color data, and secondadditional color data that are generated by applying an upscalingalgorithm to the second input color data.